Improving Energy Efficiency of Web Servers by Using a Load Distribution Algorithm and Shutting Down Idle Nodes

Polling-based load distribution (LD) algorithms suffer from two weaknesses: (i) load information exchanged during a polling session is confined to the two negotiating nodes only; (ii) as the distributed system grows in size (in terms of the number of constituent nodes), a larger number of polling sessions, and thus a higher amount of network bandwidth consumption and CPU overhead, are needed. We propose a new LD algorithm which is based on anti-tasks and load state vectors. This new algorithm avoids the above weaknesses of polling-based LD algorithms. Anti-tasks are composite agents which travel around a distributed system to facilitate the pairing up of task senders and receivers, as well as the collection and dissemination of load information. Time-stamped load information of processing nodes is stored in load state vectors which, when used together with anti-tasks, encourage mutual sharing of load information among processing nodes. Anti-tasks, which make use of load state vectors to decide their traveling paths, are spontaneously directed towards processing nodes having high transient workload, thus allowing their surplus workload to be relocated quickly. Using simulations, we evaluate the performance of our new algorithm by comparing its performance with a number of well-known polling-based load distribution algorithms. We found that our algorithm provides significant reduction of mean task response time over a large range of system sizes. The cost of achieving this performance gain in terms of CPU overhead and channel bandwidth consumption is generally comparable to the other algorithms we studied. © 1998 John Wiley & Sons, Ltd.

Describes the design and analysis of RobustWeb, a scalable and fault-tolerant World Wide Web server cluster that is based on HTTP redirection. The system consists of a set of N back-end document servers and one or more redirection servers which receive the HTTP requests and redirect them to the document servers. A load distribution algorithm is used for initial distribution of the documents on the servers. Given a specific degree of replication k, the distribution algorithm guarantees that at least k replicas of each document are present after document distribution is complete. The redirection servers redirect requests to one of the replicas with a pre-computed redirection probability. When a server fails, the redirection probabilities are recomputed using a novel algorithm based on network flow. Theis enables the load to be approximately balanced among the remaining servers, allowing for graceful degradation of the service in the event of failures. A preliminary prototype of RobustWeb has been implemented.

Clusters of GPUs are becoming commonly used to execute computationally demanding applications. Due to the frequent changes in GPU architecture, many clusters contain heterogeneous types of GPUs, leading to the problem of load distribution among the machines. In this work, we propose a load distribution algorithm for scientific applications executed in heterogeneous GPU clusters. The algorithm finds a distribution of data that minimizes the execution time of the application, by guaranteeing that all GPUs spend the same amount of time processing its assigned kernels and data. We use the algorithm to execute the simulation of large scale neuronal networks. We show that the algorithm effectively balances the load among the GPUs and reduces the execution time of the application.

The study of energy filtering management process for microgrid based on the dynamic response model of vanadium redox flow battery

A new wearable robot for upper-extremity was designed for handling heavy weights. The human-robot integrated structure constitutes a closed-chain mechanism which allows a proper load distribution between the robot and the human. The kinematic and dynamic models for this human-robot integrated exoskeleton system were presented. Through the load distribution algorithm between the human and the robot, it was shown that the robot could withstand majority of the payload. Copyright ?? 2012 IEEE.

Trailer type mobile robots have been studied from the viewpoint of control and design of nonholonomic mechanical systems in literature. However, researches for its detailed closed form kinematic and dynamic modeling are rarely being progressed. Though the trailer type mobile robot is shaped like a kinematically redundant system consisting of surplus joints, its actual kinematic characteristic is similar to a closed chain system since the motion of every trailer is constrained to the ground and the following trailers' motion is dependent on the leading trailer's motion. The exact kinematic relationship between the leading trailer and the following trailers is derived by the transfer method using the augmented generalized coordinates. A general dynamic model is derived using the Lagrangian approach and load distribution algorithm is suggested. It can be seen that the proposed approach facilitates distribution of the system load to all trailers. Forward dynamic simulation is conducted to verify the effectiveness of the suggested kinematic and dynamic models.

A Negotiation Protocol for Dynamic Load Distribution Using Batch Task Assignments

Decreasing power consumption with energy efficient data aware strategies

The article is devoted to consideration of issues related to assessing the energy efficiency of a coal mining enterprise. Coal mining enterprises are characterized by a large volume of energy intensive ore mining operations. The article presents possible ways of energy saving in the mining industry. During the research, a system of energy efficiency indicators for coal mining enterprises is presented. Materials and methods. The article proposes a system of indicators for coal enterprises based on existing methods and approaches to assessing energy efficiency. Energy consumption dependence graphs, benchmarking, and pinch analysis are considered as a starting point. Results. The study presents a system of energy efficiency indicators for coal mining enterprises. The proposed system has several levels. The existing methods and approaches for assessing this important indicator for industrial enterprises in the coal industry as a whole are considered. The author’s approach to formalizing the system of energy efficiency indicators for coal mining enterprises is proposed. The significance of energy audit as a key assessment measure is indicated and its stages are highlighted. The influencing factors determining energy costs and their reduction for a coal mining enterprise are systematized, barriers preventing the practical implementation of energy saving measures are analyzed. Discussion. The proposed metrics system provides a comprehensive framework for assessing the energy efficiency of coal mining enterprises at various levels. Its flexibility allows it to be applied to the analysis of individual equipment units, production processes, and overall enterprise performance. Its multi-level approach provides a detailed understanding of energy consumption, which allows for informed decision-making to optimize operations. At the equipment level, the metrics system evaluates the energy consumption and efficiency of individual machines and devices. At the production process level, the metrics system analyzes the energy consumption and efficiency of various stages of coal mining. At the enterprise level, the metrics system provides a comprehensive assessment of overall energy efficiency. It takes into account energy consumption at all levels and allows enterprises to compare their performance with each other and with industry benchmarks. Conclusion. Energy efficiency assessment of a coal mining enterprise allows to understand how and where energy is used, where its use can be improved, and how to reduce its costs. To conduct an energy efficiency assessment, the article proposes a system of indicators, highlighting the features of an energy audit. The main advantage of the proposed system of indicators is that it covers a wide range of energy consumption indicators, which are carefully selected and located at different levels of detail. In general, a balanced approach to the level of detail and generalization in the system of indicators provides flexibility in adapting indicators to specific research questions and helps to interpret the results in the context of structural differences between energy systems. Resume. Overall, the proposed metrics system offers a comprehensive approach to analyzing the energy efficiency of coal mining enterprises, covering all levels of operations. Its use allows enterprises to improve energy efficiency, reduce operating costs, and contribute to a more sustainable coal mining industry. Suggestions for practical applications and directions for future research. The use and implementation of the developed system at a coal mining company allows it to improve energy efficiency, reduce operating costs and contribute to a more sustainable coal mining industry.

To assist in the implementation of carbon peaking and carbon neutrality in China, due to the contradiction between the increasing energy consumption of residential buildings in China and the higher energy efficiency goals, this paper illustrates that the energy consumption constitution of residential buildings in the whole life cycle and then puts forward comprehensive energy efficiency strategies. With literature and statistical data, the main part of building energy consumption lies in the materialization and use phases, which both will be continually increasing, and divided into energy utilization and waste. By inducing the energy consumption in the use phase, the energy consumption of residential buildings can be further classified into the energy consumption of indoor environments, residential behavior, and public facilities, where the internal factor of continuous increase are all elaborated. Via the analysis of energy waste causes, this paper constructs a model of energy consumption in residential buildings, reveals that the key to energy efficiency in residential buildings lies in scientific decision-making, lifestyle improvement, and appropriate energy efficiency technologies and measures adoption, and points out that promoting building energy efficiency through the whole life cycle of buildings and building activities is needed to achieve carbon compliance and carbon neutrality.

Research on the building energy efficiency design strategy of Chinese universities based on green performance analysis

An Internet of Things based energy efficiency monitoring and management system for machining workshop

Highlights on energy efficiency improvements: a case of a small brewery

Web services QoS management frameworks proposed in the literature deal essentially with issues such as QoS specification, QoS-based discovery and selection, and QoS monitoring of Web services. However, only few works have considered the issue of load distribution in a Web services context. In this paper, we investigate three models that might be used to achieve load distribution in a Web services environment. We focus on load distribution at the operation level by considering the assignment of methods execution to appropriate Web services according to some selection policies. The experiments we have conducted using the broker-oriented model have shown that better results are obtained using the random policy for Web service selection.

Building consumes 40% of global energy consumption which contributes for such a majority amount of carbon dioxide emission. Enhancing the energy efficiency strategies in buildings by retrofitting through different approaches is essential for reducing end user on the amount of energy consumption and carbon footprint emission. Previous research shows that only a few studies have been conducted on retrofitting the energy performance on Rest and Service Area yet the result shows that lack of technical feasibility practice was reviewed. Hence, this paper explores the energy efficiency strategy by improving the lighting performance based on 24 hours service building at Rest and Service Area Ayer Keroh Northbound Malaysia. The simulation that was performed in lighting energy consumption was EnergyPLUS software, Autodesk Revit and RELUX Plug in tool in Revit. Preliminary study was conducted to identity the problem on energy performance at Rest and Service Area Ayer Keroh by determine the total energy consumption by sources and Building Energy Intensity [BEI]. The result shows lighting contributes to the most total load consumption due to lack of energy conservation management and energy efficiency strategy practices. The lighting simulation scenarios was created to enhance the energy consumption performance and reduced the irrelevant carbon footprint emission. The simulation in Revit and EnergyPLUS showed 17% and 49% reduction respectively on the end load of lighting energy consumption by reducing the overall time operation and daylight control dimming system.